Phagocytic Activity Of Human Neutrophils Research Articles

Immunomodulatory Potential of the Industrialized Houttuynia cordata Fermentation Product In Vitro and in Wistar Rats.

Houttuynia cordata fermentation products (HCFPs) are produced and widely used as dietary supplements for health and immune support. However, the effect on immune function for these products has not been clearly demonstrated. In this study, soluble fractions of the selected HCFP were used for determination of the immunomodulatory potential, both in vitro and in animal models. Viability and proliferation of rat splenocytes and phagocytic activity of human neutrophils were evaluated. Studies on immunomodulatory effects, including hematological parameters, mitogen-driven lymphocyte proliferation and hemagglutination, were performed in both healthy and immunosuppressed rats. Soluble fraction of the selected HCFP significantly enhanced phagocytic activity of human neutrophils and tended to stimulate splenocyte viability and proliferation. There was no morbidity or mortality for administration of a 14-day regimen of the selected HCFP in both male and female rats. The healthy rats treated with HCFP gained body weight less than the control group, suggesting a reduction in calorie intake. Moreover, low dose of HCFP caused an increased B cell proliferation in ex-vivo, which was related to the increased antibody titer against SRBC in immunosuppressed rats. Our results indicate that the selected HCFP enhances the phagocytic activity of the neutrophils and augments the antibody production in immunosuppressed rats.

Vitex negundo L. leaf extract inhibits IL-6 and TNF-α secretion and phagocytosis in human leukocytes

Vitex negundo L. is used as an anti-inflammatory agent in Ayurveda and Sri Lankan traditional medicine. Here, the anti-inflammatory effects of an aqueous leaf extract (ALE) of V. negundo L. was investigated. The inhibitory effects of freeze-dried ALE (15.7–500 μg/mL) against interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-α (TNFα) secretion by human mononuclear cells, phagocytic activity of human neutrophils, and reactive oxygen species (ROS) and nitric oxide (NO) production by human leukocytes were tested in vitro. The inhibitory effects were dose dependent, and the strongest effect was observed at 500 μg/mL (P < 0.05). ALE caused 58.0 ± 1.0 % and 26.1 ± 2.0 % inhibition of IL-6 and TNFα secretion, respectively, whereas the positive control, Andrographis paniculata, caused complete inhibition. Phagocytic activity and ROS production were inhibited by 55 ± 4.5 % and 58.6 ± 8.6 %, respectively, whereas the positive controls, Ixora coccinea and diphenyleneiodonium chloride, caused 100 ± 4.4 % and 80 ± 6.4 % inhibition, respectively. ALE markedly inhibited NO production (87.5 ± 17.7 %), and the effect was comparable to that of the positive control, N-monomethyl-l-arginine (95.0 ± 1.0 %). The membrane-stabilizing activity of ALE (0.01–100 μg/mL) was assessed using heat-induced lysis of human erythrocytes. The highest membrane stabilizing activity (91 %) was observed at 0.01 μg/mL and was comparable with that of aspirin (positive control; 86.6 ± 0.51 %). These inhibitory effects may be the mechanisms through which V. negundo L. elicits its anti-inflammatory activities and support the traditional use of V. negundo L. as an anti-inflammatory agent.

Standardized ethanol extract, essential oil and zerumbone of Zingiber zerumbet rhizome suppress phagocytic activity of human neutrophils

BackgroundZingiber zerumbet rhizome and its bioactive metabolites have previously been reported to exhibit innumerable pharmacological properties particularly anti-inflammatory activities. In the present study, the 80% ethanol extract, essential oil and zerumbone of Z. zerumbet rhizomes were explored for their in vitro immunosuppressive properties on chemotaxis, CD11b/CD18 expression, phagocytosis and chemiluminescence of isolated human polymorphonuclear neutrophils (PMNs).MethodsThe extract was analyzed quantitatively by performing a validated reversed phase high performance liquid chromatography (RP-HPLC). Zerumbone was isolated by chromatographic technique while the essential oil was acquired through hydro-distillation of the rhizomes and further analyzed by gas chromatography (GC) and GC-MS. Chemotaxis assay was assessed by using a 24-well cell migration assay kit, while CD18 integrin expression and phagocytic engulfment were measured using flow cytometry. The reactive oxygen species (ROS) production was evaluated by applying lucigenin- and luminol-enhanced chemiluminescence assays.ResultsZerumbone was found to be the most abundant compound in the extract (242.73 mg/g) and the oil (58.44%). Among the samples tested, the oil revealed the highest inhibition on cell migration with an IC50 value of 3.24 μg/mL. The extract, oil and zerumbone showed moderate inhibition of CD18 integrin expression in a dose-dependent trend. Z. zerumbet extract showed the highest inhibitory effect on phagocytic engulfment with percentage of phagocytizing cells of 55.43% for PMN. Zerumbone exhibited strong inhibitory activity on oxidative burst of zymosan- and PMA-stimulated neutrophils. Zerumbone remarkably inhibited extracellular ROS production in PMNs with an IC50 value of 17.36 μM which was comparable to that of aspirin.ConclusionThe strong inhibition on the phagocytosis of neutrophils by Z. zerumbet extract and its essential oil might be due the presence of its chemical components particularly zerumbone which was capable of impeding phagocytosis at different stages.

Inhibitory effects of compounds from Phyllanthus amarus on nitric oxide production, lymphocyte proliferation, and cytokine release from phagocytes.

Standardized extract of Phyllanthus amarus has previously been shown to have a strong inhibitory effect on phagocytic activity of human neutrophils. The current study was carried out to evaluate the effects of constituents of the extract of P. amarus on nitric oxide (NO) production as well as lymphocyte proliferation and cytokine release from phagocytes. Three compounds, ethyl 8-hydroxy-8-methyl-tridecanoate, 7β,19α dihydroxy-urs-12-ene, and 1,7,8-trihydroxy-2-naphtaldehyde, together with seven known compounds were isolated from the whole plant of P. amarus. The isolated compounds and reference standards, ie, gallic acid, ellagic acid, corilagin, and geraniin, which were quantitatively analyzed in the extracts, were evaluated for their effects on immune cells. Among the compounds tested, the lignans, especially phyltetralin and phyllanthin, showed strong inhibition on lymphocyte proliferation with half maximal inhibitory concentration (IC50) values of 1.07 μM and 1.82 μM, respectively. Ethyl 8-hydroxy-8-methyl-tridecanoate and 1,7,8-trihydroxy-2-naphtaldehyde exhibited strong inhibition on nitric oxide production with IC50 values of 0.91 μM and 1.07 μM, respectively. Of all the compounds, corilagin was the strongest inhibitor of tumor necrosis factor-α release with an IC50 value of 7.39 μM, whereas geraniin depicted the strongest inhibitory activity on interleukin-1β release with an IC50 value of 16.41 μM. The compounds constituting the extract of P. amarus were able to inhibit the innate immune response of phagocytes at different steps.

Inhibitory Effects of the Standardized Extract of Phyllanthus amarus on Cellular and Humoral Immune Responses in Balb/C Mice.

Phyllanthus amarus has been shown to have strong inhibitory effects on phagocytic activity of human neutrophils and on cellular immune responses in Wistar-Kyoto rats. In this study, we investigated the effects of daily treatment of standardized extract of P. amarus at 50, 100 and 200 mg/kg for 14 days in Balb/C mice by measuring the myeloperoxidase activity (MPO), nitric oxide (NO) release, macrophage phagocytosis, swelling of footpad in delayed type hypersensitivity (DTH), and serum immunoglobulins, ceruloplasmin and lysozyme levels. Qualitative and quantitative analyses of the extract using validated reversed-phase HPLC methods identified phyllanthin, hypophyllanthin, corilagin and geraniin as the biomarkers. Significant dose-dependent inhibitions of MPO activity and NO release were observed in treated mice. The extract also inhibited E. coli phagocytic capacity of peritoneal macrophages of treated mice and inhibited the sheep red blood cells (sRBC)-induced swelling rate of mice paw in the DTH. There was also a significant decrease in non-specific humoral immunity including ceruloplasmin and lysozyme levels in the extract-fed groups as well as the release of serum level immunoglobulins. The strong inhibitory effects of the extract on the cellular and humoral immune responses suggest the potential of the plant to be developed as an effective immunosuppressive agent. Copyright © 2016 John Wiley & Sons, Ltd.

In vitro effect of dexmedetomidine on the respiratory burst of neutrophils.

The immunosuppressive effects of dexmedetomidine, a highly selective and widely used a2-adrenoceptor agonist for sedation, analgesia, and stress management, are investigated in vitro. In the present study, the respiratory burst of human neutrophils separated from venous blood was evaluated with dexmedetomidine treatment after Escherichia coli stimulation. The effects of five concentrations of dexmedetomidine (1, 5, 10, 50, 100 μg/mL) were evaluated by rhodamine in a flow cytometer. The nitric oxide (NO) production and nitric oxide synthase (iNOS) activity were also determined by using commercial kits. The results were compared to the positive control responses (respiratory burst without drug). We found that dexmedetomidine significantly suppressed respiratory burst, NO production, and iNOS activity after stimulation with E. coli, in a dose-dependent manner. The suppressive effects of dexmedetomidine on phagocytic activity of human neutrophils were associated with respiratory burst coupled with NO production.

Correlation between the major components of Phyllanthus amarus and Phyllanthus urinaria and their inhibitory effects on phagocytic activity of human neutrophils

BackgroundRecently, we have highlighted the immunomodulatory activity of the standardized extracts of Phyllanthus amarus and P. urinaria. The present study was carried out to correlate between the prevalent constituents of the herbs and their inhibitory effects on phagocytic activity of human neutrophils.MethodsThe compounds, gallic acid, ellagic acid, corilagin, geraniin, phyllanthin and hypophyllanthin were identified and quantitatively analyzed in the extracts of Phyllanthus amarus and P. urinaria obtained from Malaysia and Indonesia by using a validated reversed phase high performance liquid chromatography (RP-HPLC) method. The standardized extracts and the pure compounds were evaluated for their effects on chemotaxis, β2 integrin (CD18) expression, phagocytosis and chemiluminescence of human phagocytes. Chemotactic activity was assessed using the Boyden chamber technique, inhibition of CD18 expression and phagocytic ability were tested with the aid of flow cytometry, while effect on the respiratory burst was investigated using a luminol-based chemiluminescence assay.ResultsAll plant extracts strongly inhibited migration of the phagocytes with the Malaysian P. amarus depicting the highest inhibitory activity. Amongst the compounds tested, geraniin demonstrated the strongest inhibitory activity on chemotaxis of polymorphonuclear leukocytes (PMNs) and monocytes with IC50 values of 1.09 and 1.69 μM, respectively, which were lower than that of ibuprofen. All plant extracts and pure compounds exhibited high inhibitory activity on the oxidative burst of zymosan and PMA stimulated leukocytes. Geraniin and corilagin exhibited exceptionally strong inhibition on the reactive oxygen species (ROS) activity with IC50 values lower than aspirin. The plant extracts exhibited moderate inhibition of E. coli uptake by monocytes but weak effect on PMNs. Of all the compounds, phyllanthin at 50 μg/mL exhibited the highest engulfment inhibitory activity with percentage of phagocytizing cells of 14.2 and 27.1% for PMNs and monocytes, respectively. All plants and compounds tested possessed weak effect on CD18 expression on leukocytes except for hypophyllanthin and phyllanthin which exhibited significant inhibitory effect.ConclusionThe strong inhibition of the extracts on the phagocytic activity of neutrophils was due to the presence of their major constituents especially geraniin, corilagin, phyllanthin and hypophllanthin which were able to modulate the innate response of phagocytes at different steps.

Inhibitory Effects of Areca Nut Extract on Expression of Complement Receptors and Fc Receptors in Human Neutrophils

Chewing of areca quid increases the prevalence of periodontal diseases. Areca nut extract (ANE) inhibits the phagocytic activity of human neutrophils. This in vitro study investigates the effects of ANE on complement- and antibody-opsonized phagocytosis by neutrophils. Expression of complement receptors, Fc receptors, and F-actin in ANE-treated neutrophils is also analyzed. The viability of ANE-treated neutrophils was determined using the propidium iodide staining method. The possible effects of ANE on the expression of complement receptors and Fc receptors were examined using an immunofluorescence staining method followed by flow cytometry and confocal laser scanning microscopy. The phagocytic activity of neutrophils against complement or immunoglobulin (Ig)G-opsonized fluorescent beads was analyzed using flow cytometry. Expression of F-actin was determined using confocal laser scanning microscopy. ANE significantly inhibited the production of complement receptors (CR1, CR3, and CR4) and Fc receptors (FcγRII and FcγRIII) in a concentration-dependent manner. Treatment of neutrophils with ANE significantly impaired their ability to phagocytose fluorescent beads. ANE also inhibited phagocytosis of fluorescent beads that were opsonized by complement or IgG. Moreover, expression of F-actin was inhibited after ANE treatment. ANE inhibits the complement- and IgG-mediated neutrophil phagocytosis that may result from reduction of the expression of complement receptors, Fc receptors, and F-actin formation after ANE treatment. The findings suggest that areca nut chewing may jeopardize the defensive functions of neutrophils and affect periodontal health.

Inhibitory Effects of Standardized Extracts of Phyllanthus amarus and Phyllanthus urinaria and Their Marker Compounds on Phagocytic Activity of Human Neutrophils.

The standardized methanol extracts of Phyllanthus amarus and P. urinaria, collected from Malaysia and Indonesia, and their isolated chemical markers, phyllanthin and hypophyllanthin, were evaluated for their effects on the chemotaxis, phagocytosis and chemiluminescence of human phagocytes. All the plant extracts strongly inhibited the migration of polymorphonuclear leukocytes (PMNs) with the Malaysian P. amarus showing the strongest inhibitory activity (IC50 value, 1.1 µg/mL). There was moderate inhibition by the extracts of the bacteria engulfment by the phagocytes with the Malaysian P. amarus exhibiting the highest inhibition (50.8% of phagocytizing cells). The Malaysian P. amarus and P. urinaria showed strong reactive oxygen species (ROS) inhibitory activity, with both extracts exhibiting IC50 value of 0.7 µg/mL. Phyllanthin and hypophyllanthin exhibited relatively strong activity against PMNs chemotaxis, with IC50 values slightly lower than that of ibuprofen (1.4 µg/mL). Phyllanthin exhibited strong inhibitory activity on the oxidative burst with an IC50 value comparable to that of aspirin (1.9 µg/mL). Phyllanthin exhibited strong engulfment inhibitory activity with percentage of phagocytizing cells of 14.2 and 27.1% for neutrophils and monocytes, respectively. The strong inhibitory activity of the extracts was due to the presence of high amounts of phyllanthin and hypophyllanthin although other constituents may also contribute.

Zinc(II) complexes with novel 1,3-thiazine/pyrazole derivative ligands: Synthesis, structural characterization and effect of coordination on the phagocytic activity of human neutrophils

The new ligands 2-(1-pyrazolil)-1,3-thiazine (PzTz), 2-(3,5-dimethyl-1-pyrazolil)-1,3-thiazine (DMPzTz) and 2-(3,5-diphenyl-1-pyrazolil)-1,3-thiazine (DPhPzTz) and the complexes [ZnCl 2(H 2O)(PzTz)] ( 1), [ZnCl 2(DMPzTz)] ( 2) and [ZnCl 2(DPhPzTz)] ( 3) have been isolated and then characterized by elemental analysis, IR spectra and UV–Vis spectroscopy. Besides, the crystal structure of ligands PzTz and DPhPzTz and complexes 1– 3 have been determined by single-crystal X-ray diffraction. In 1, the geometry around the Zn(II) atom can be considered a highly distorted trigonal bipyramid, with the metallic atom bonded to two chlorine atoms, one water molecule and one bidentate PzTz ligand. In 2 and 3, the environment around the metal ion can be described as a distorted tetrahedron with the zinc atom coordinated to one bidentate organic ligand molecule and two chloro ligands. In addition, the phagocytic function of human neutrophils treated with complexes 1– 3, their organic ligands and ZnCl 2 has been evaluated. The activity of cells enhanced in samples treated with 1, 2 and 3 with respect to the ones to which the inorganic salt, PzTz, DMPzTz or DPhPzTz were added.

Synthesis and structural characterization of two new copper(II) complexes with thiazoline derivative ligands: Influence of the coordination on the phagocytic activity of human neutrophils

Two new copper(II) complexes dichloro[2-(3,4-dichlorophenyl)imine- κN-(2-thiazolin- κN-2-yl)thiazolidine]copper(II) [CuCl 2(TdTn)] ( 1) and dichloro[2-(3,4-dichlorophenyl)imine- κN-(2-thiazolin- κN-2-yl)tetrahydrothiazine]copper(II) [CuCl 2(TzTn)] ( 2) were synthesized, then characterized by elemental analysis, UV–Vis–NIR diffuse reflectance, electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, infrared spectroscopy, and finally their crystal structures determined by X-ray diffractometry. The structural determination of [CuCl 2(TzTn)] ( 2) was made by conventional single-crystal diffractometry, whereas the procedure followed to resolve the crystal structure of [CuCl 2(TdTn)] ( 1) by means powder diffractometry using direct-space methods with a ‘Monte–Carlo/parallel tempering’ search algorithm. A final refinement of the crystal structure was performed using the Rietveld method. It was found that the environment around the copper(II) ion for both complexes can be described as having a distorted tetrahedral geometry, with the metallic atom coordinated with two chlorides, one imine nitrogen and one thiazoline nitrogen. The biological activity of the complexes, inorganic salt and their ligands has been evaluated by examining their phagocytic activity on human neutrophils. This activity enhances in the case of the samples treated with [CuCl 2(TdTn)] ( 1) and [CuCl 2(TzTn)] ( 2) with respect to the ones to which CuCl 2, TdTn or TzTn was added.

Gene expression profile and pathogenicity of biofilm-forming Prevotella intermedia strain 17.

BackgroundPrevotella intermedia (P. intermedia), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. P. intermedia strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials in vitro from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays.ResultsStrain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (σE; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media.ConclusionThese results demonstrate that the capacity to form biofilm in P. intermedia contribute to their resistance against host innate defence responses.

Hydrogen peroxide increases the phagocytic function of human neutrophils by calcium mobilisation

We have studied the effect of exogenous administration of hydrogen peroxide (H(2)O(2)) on phagocytic activity of human neutrophils. The treatment of cells with increasing concentrations of H(2)O(2) evoke a significant elevation of phagocytic function assayed as phagocytic index, percentage and efficiency; and was similar to that induced by the calcium mobilising agonist formyl-methionyl-leucyl-phenylalanine (fMLP). This stimulatory effect was reduced by pre-treatment of neutrophils with catalase and abolished in neutrophils loaded with the intracellular calcium quelator dimethyl BAPTA. In the absence of extracellular calcium, treatment of cells with H(2)O(2) resulted in a increase in [Ca(2+)]( i ), indicating the release of calcium from intracellular stores. H(2)O(2) abolished the typical calcium release stimulated by the physiological agonist fMLP, while depletion of agonist-sensitive calcium pools by fMLP was able to prevent H(2)O(2)-induced calcium release. We conclude that H(2)O(2) induces calcium release from agonist-sensitive stores and consequently increase the phagocytosis process.

Synthesis, structural characterization and influence on the phagocytic activity of human neutrophils of thiazoline and thiazine derivative ligands and their zinc(II) complexes

The zinc(II) complexes dichloro[2-(3,4-dichlorophenyl)imino-κN-(2-thiazolin-κN-2-yl)thiazolidine]zinc(II) (1) and dichloro[2-(3,4-dichlorophenyl)imino-κN-(4H-5,6-dihydro-1,3-thiazin-κN-2-yl)tetrahydrothiazine]zinc(II) (2) have been isolated and characterized in the solid state by X-ray diffraction, elemental analysis and IR spectra. In both complexes, the environment around the zinc(II) ion may be described as a distorted tetrahedral geometry, with the metallic atom coordinated to two chlorine atoms [Zn–Cl(1)=2.218(1)Å; Zn–Cl(2)=2.221(1)Å], one imino nitrogen [Zn–N(3)=2.042(2)Å] and one thiazoline nitrogen [Zn–N(1)=2.022(2)Å] in complex 1 and to two chlorine atoms [Zn–Cl(1)=2.216(1)Å; Zn–Cl(2)=2.192(1)Å], one imino nitrogen [Zn–N(3)=2.045(2)Å] and one thiazine nitrogen [Zn–N(1)=2.039(2)Å] in complex 2. In addition, we also report in this study the crystal structure of the 2-(3,4-dichlorophenyl)imino-N-(2-thiazolin-2-yl)thiazolidine (TdTn) ligand as well as the synthesis and characterization by X-ray diffraction, 1H and 13C NMR spectra, elemental analysis, IR and electronic spectra of the 2-(3,4-dichlorophenyl)imino-N-(4H-5,6-dihydro-1,3-thiazin-2-yl)tetrahydrothiazine (TzTz) ligand. Besides, we study the phagocytic function in humans neutrophils treated with each complex and ligand aforementioned.

Milli Gauss pursed Magnetic Field Applied Phosphate Buffeted Saline Solution Elevates Intracellular Ca2+ Level and Stimulates Phagocytic Activity of Human Neutrophils

Milli Gauss pursed Magnetic Field Applied Phosphate Buffeted Saline Solution Elevates Intracellular Ca2+ Level and Stimulates Phagocytic Activity of Human Neutrophils

Kinetics of the biphasic modulation of phagocytosis

A kinetic model for the biphasic modulation of phagocytosis, fulfilling the requirements of biochemistry of ligand‐binding reactions, was constructed on the basis of a biocybernetic notion of the feedback loop‐containing (autocalytic) process. Using boundary conditions for parameters of possible kinetic models, a single model was selected, in which the biphasic modulatory effect exerted on a phagocytic activity of human neutrophils by the peptide preparation Immax A1 was described as a result of mutual counteraction of two antagonistic compounds (stimulator and inhibitor of phagocytosis) competing for bacterial chemotactic peptide receptors on neutrophils. This model, in which the integrated luminescence‐based normalised measure of inhibition of phagocytosis stands for the reaction rate, was found to have a form of a 2:3 rational function of the peptide preparation concentration. A corresponding stoichiometric scheme, describing the binding both of the inhibitor and of the stimulator to neutrophils, was constructed on the assumption that inhibition was not total when connected with the generation of three‐component complexes, stimulator‐neutrophil‐inhibitor.

Effects of Hydroxyethyl Starch and Modified Fluid Gelatine on Phagocytic Activity of Human Neutrophils and Monocytes – Results of a Randomized, Prospective Clinical Study

Background: Hydroxyethyl starch (HES) and modified fluid gelatine (MFG) are commonly used to replace intravascular volume. Experimental studies have revealed either an inhibitory effect or no effect of colloidal fluids on leukocyte function. We investigated prospectively the influence of several 6% HES (MW (Da) / degree of substitution: 70,000/0.5; 200,000/0.5; 450,000/0.7) and 3% MFG (MW 30,000 Da) solutions on phagocytic activity of circulating polymorphonuclear neutrophils (PMNs) and monocytes. Patients and Methods: Following ethics committee approval, venous blood was drawn from 40 urological patients (n = 10 in each group) before and 1 h after infusion with 10 ml/kg of one of the above-mentioned solutions. None of the patients had any underlying disease known to interfere with leukocyte function. The phagocytic activity of neutrophils and monocytes was measured by the uptake of fluorescein isothiocyanate(FITC)-labelled, opsonized bacteria by means of flow cytometry. Results: Phagocytic capacity of both neutrophils (94.01 ± 2.64%; mean ± SEM) and monocytes (89.80 ± 3.36%) was decreased following the application of MFG (p ≤ 0.05). No significant differences could be found in phagocytic activity following HES administration, regardless of molecular weight and degree of substitution. Conclusion: Our results indicate that leukocyte phagocytosis may vary according to the type of colloidal fluids used. The HES solutions investigated did not affect phagocytic activity of circulating PMNs and monocytes. However, leukocyte phagocytosis was impaired after MFG application.

Bovine Lactoferrin Stimulates the Phagocytic Activity of Human Neutrophils: Identification of Its Active Domain

Bovine LF (bLF) at concentrations in the range of 50–250 μg/ml enhanced the phagocytic activity of human neutrophils as determined by measuring the incorporation of FITC-labeled latex beads by flow cytometry. The stimulatory effect of bLF was not abrogated by hydrolysis with pepsin. Bovine lactoferricin (bLFcin), which is a bactericidal fragment purified from a pepsin hydrolysate of bLF (bLFH), also enhanced the phagocytic activity, whereas, in contrast, the fraction of bLFH depleted of bLFcin showed no stimulatory effect. The phagocytosis-enhancing activity of bLF still remained after washing the neutrophils, following exposure to bLF. Also, bLF pretreatment of the latex beads stimulated their uptake. These results demonstrate that bLF is effective in promoting the phagocytic activity of human neutrophils. This activity appears to be due to its bLFcin domain and may involve dual mechanisms of direct binding to neutrophils and opsonin-like activity.

Granulocyte-colony stimulating factor improves suppressed neutrophilic phagocytosis against hypernatremic condition

Phagocytic activity is an important function of neutrophilis in the host defense against burn wound infection. In a previous report we demonstrated hypernatremic suppression of neutrophils at sodium concentrations comparable to these in the zone of stasis in the burn wound. At this site the osmotic pressure will be elevated as a result of several factors, especially to increased water loss from the burn wound surface. In this study the effect of granulocyte-colony stimulating factor (G-CSF) on phagocytic activity of human neutrophils against hypernatremic suppression is investigated in vitro. In the G-CSF group 150 ng of G-CSF was added to four blood samples (5 ml each). Phagocytic activities of the control group ( n = 10) showed 88.3 ± 4.1 per cent (means ± SD) at 140 mmol/l of sodium concentration, 68.2 ± 6.9 at 180, 57.6 ± 10.1 at 220, and 48.6 ± 8.6 at 260 mmol/l. The G-CSF group showed 88.2 ± 7.0 at 140, 79.9 ± 9.4 at 180, 71.4 ± 7.4 at 220, and 56.5 ± 14.1 at 260 mmol/l. At 180 and 220 mmol/l significant differences were recognized. Results of this study suggest a favourable effect of G-CSF on suppressed neutrophils under the hypernatremic conditions.

Flow cytometric assay of phagocytic activity of human neutrophils and monocytes in whole blood by neutral red uptake

Flow cytometric assay of phagocytic activity of human neutrophils and monocytes in whole blood by neutral red uptake